The last two people on Earth were in the same room.
When the Destruction Wave swept over everything the world came to an end. Civilisation boiled away like the seas. Mountains crumbled in the blink of an eye. Some small buildings survived but most were burned shells surrounded by broken glass. No one but those two had lived through it.
"What have you done?"
"The only thing that made any sense. It had to come to an end. Had to."
Steve put his head in his hands and thought about that for a moment. She was insane, she had to be, but that didn't excuse Vanessa's actions.
"Don't worry, though," she said, shrugging in her chair, "you did your part. You tried to stop me."
"I should have just put a bullet in your skull when I knew what you were capable of. Instead I brought you here. Detainment..."
"And now we have to be the only two left. The Jailor and his only Prisoner. When one of us dies the other will be the sum total of the human race. All those thousands of years will end with either the most prolific murderer of all time or the man who couldn't bring himself to kill one person."
"I've killed."
"But not the right person."
"You didn't do this alone. Obviously. You draw your power from what exactly?"
"The Hive," Vanessa answered. Her voice was flat; matter of fact; simple. The kind of voice used when a child asks what colour the sky is or a man with a form wants to know your name. "Where else?"
"There are a few places. Right at the end there were a lot of technologies we could use to emulate the sort of things you guys were capable. I suppose you may as well know, seeing as it's just the two of us, but we were in the middle of a cold war. China. Russia. America. They were all running their own programs. It seems like you heated the whole thing up a bit."
"I'd heard rumours. This place was evidence of at least one place. The war would have been brutal, wouldn't it? Billions of people would have suffered and died terribly. What I gave them was quick and merciful."
"How did you do it? No Node could be that powerful."
"I'm a parasite, capable of drawing from the Hive at the expense of others. I got lucky and found an Assimilator, never did get her name. She grew me my own private Hive of thousands. All the time I've been here I've been drawing from them until that little firework display was possible. It got very noisy but now... Thank God it's silent."
"If I had shot you then I could have saved the world."
"I saved the world. You would have condemned it to war."
Steve opened his jacket, showing Vanessa a holster. Inside was a service handgun with the last nine bullets in the world. He placed it on the table for Vanessa to get a close look at.
"I already did stop you."
Vanessa's eyes narrowed.
"I'm like you," Steve continued, "but I don't have a natural Hive. One of those programs created me and gave me a remarkable ability. Time travel, of a sort. You see, when I kill someone I can remove them from existence entirely. It makes me the ultimate assassin because once I kill you time reshapes itself. And right now you have no Hive to draw from, no power to stop me -"
"Never said that," Vanessa cut in. She rose quickly, purple energy swirling around her.
Steve panicked, grabbing the gun, raising it and squeezing the trigger.
The field around Vanessa flickered. All nine shots dissolved before getting to their target.
"Oh, Steve, I wish you hadn't done that. Now I can't let you live."
One moment Steve was standing in the room, The next a blast of energy hit his neck, snapping it.
Sixty years earlier Steve was born.
He grew up. Went to school. Graduated and fell into a life of crime. Then the recruiters came and taught him how to sharpen his skills. The cold wars began, the Hive rose, and all Steve was introduced to Lifeline.
He avoided death six times. All the time he remembered what he had seen at the end of the world. He remembered Vanessa's face, he remembered what happened, And when he saw her he shot her.
The agent he worked with, a member of the Hive, was a man who could remove people from existence. He took care of the body while Steve went back to the office.
Lifeline, an implanted ability, was a miracle. Die, any way you like, and you would find yourself at the beginning of your own timeline with every memory of your previous life. Small things would fade but the big stuff, like the face of the woman who would destroy the world, never went away.